Motor recovery beginning 23 years after ischemic stroke
We report a remarkable case of stroke recovery beginning 23 yr after a severe stroke due to embolization from the innominate artery and subclavian artery, resulting from compression of the right subclavian artery by a cervical rib. The patient had a large right frontoparietal infarction with severe left hemiparesis and a totally nonfunctional spastic left hand. He experienced some recovery of hand function that began 23 yr after the stroke, 1 yr after he took up regular swimming. As a result, intensive physiotherapy was initiated, with repetitive large muscle movement and a spring-loaded mechanical orthosis that provides r...
Source: Journal of Neurophysiology - August 1, 2017 Category: Neurology Authors: Sörös, P., Teasell, R., Hanley, D. F., Spence, J. D. Tags: Research Articles Source Type: research
Learning temporal context shapes prestimulus alpha oscillations and improves visual discrimination performance
Time is an inseparable component of every physical event that we perceive, yet it is not clear how the brain processes time or how the neuronal representation of time affects our perception of events. Here we asked subjects to perform a visual discrimination task while we changed the temporal context in which the stimuli were presented. We collected electroencephalography (EEG) signals in two temporal contexts. In predictable blocks stimuli were presented after a constant delay relative to a visual cue, and in unpredictable blocks stimuli were presented after variable delays relative to the visual cue. Four subsecond delay...
Source: Journal of Neurophysiology - August 1, 2017 Category: Neurology Authors: Toosi, T., K. Tousi, E., Esteky, H. Tags: Research Articles Source Type: research
Transcribing the connectome: roles for transcription factors and chromatin regulators in activity-dependent synapse development
The wiring of synaptic connections in the developing mammalian brain is shaped by both intrinsic and extrinsic signals. One point where these regulatory pathways converge is via the sensory experience-dependent regulation of new gene transcription. Recent studies have elucidated a number of molecular mechanisms that allow nuclear transcription factors and chromatin regulatory proteins to encode aspects of specificity in experience-dependent synapse development. Here we review the evidence for the transcriptional mechanisms that sculpt activity-dependent aspects of synaptic connectivity during postnatal development and disc...
Source: Journal of Neurophysiology - August 1, 2017 Category: Neurology Authors: Chen, L.-F., Zhou, A. S., West, A. E. Tags: Reviews Source Type: research
Enhanced brain responses to color during smooth-pursuit eye movements
Eye movements alter visual perceptions in a number of ways. During smooth-pursuit eye movements, previous studies reported decreased detection threshold for colored stimuli and for high-spatial-frequency luminance stimuli, suggesting a boost in the parvocellular system. The present study investigated the underlying neural mechanism using EEG in human participants. Participants followed a moving target with smooth-pursuit eye movements while steady-state visually evoked potentials (SSVEPs) were elicited by equiluminant red-green flickering gratings in the background. SSVEP responses to colored gratings were 18.9% higher dur...
Source: Journal of Neurophysiology - August 1, 2017 Category: Neurology Authors: Chen, J., Valsecchi, M., Gegenfurtner, K. R. Tags: Rapid Reports Source Type: research
Cerebellar patients do not benefit from cerebellar or M1 transcranial direct current stimulation during force-field reaching adaptation
Several studies have identified transcranial direct current stimulation (tDCS) as a potential tool in the rehabilitation of cerebellar disease. Here, we tested whether tDCS could alleviate motor impairments of subjects with cerebellar degeneration. Three groups took part in this study: 20 individuals with cerebellar degeneration, 20 age-matched controls, and 30 young controls. A standard reaching task with force-field perturbations was used to compare motor adaptation among groups and to measure the effect of stimulation of the cerebellum or primary motor cortex (M1). Cerebellar subjects and age-matched controls were teste...
Source: Journal of Neurophysiology - August 1, 2017 Category: Neurology Authors: Hulst, T., John, L., Küper, M., van der Geest, J. N., Göricke, S. L., Donchin, O., Timmann, D. Tags: Research Articles Source Type: research
Hierarchical differences in population coding within auditory cortex
In this study, we compared population coding between primary and secondary auditory cortex. Our findings demonstrate striking differences between the two areas and highlight the importance of considering the diversity of neural structures as we develop models of population coding. (Source: Journal of Neurophysiology)
Source: Journal of Neurophysiology - August 1, 2017 Category: Neurology Authors: Downer, J. D., Niwa, M., Sutter, M. L. Tags: Research Articles Source Type: research
Multisensory coding in the multiple-demand regions: vibrotactile task information is coded in frontoparietal cortex
At any given moment, our brains receive input from multiple senses. Successful behavior depends on our ability to prioritize the most important information and ignore the rest. A multiple-demand (MD) network of frontal and parietal regions is thought to support this process by adjusting to code information that is currently relevant (Duncan 2010). Accordingly, the network is proposed to encode a range of different types of information, including perceptual stimuli, task rules, and responses, as needed for the current cognitive operation. However, most MD research has used visual tasks, leaving limited information about whe...
Source: Journal of Neurophysiology - August 1, 2017 Category: Neurology Authors: Woolgar, A., Zopf, R. Tags: Research Articles Source Type: research
The cerebellum contributes to proprioception during motion
Proprioception, the sense of limb position and motion, is essential for generating accurate movements. Limb position sense has typically been studied under static conditions (i.e., the fixed position of a limb in space), with less known about dynamic position sense (i.e., limb position during movement). Here we investigated how a person’s estimate of hand position varies when using spatial or temporal information to judge the unseen hand’s location during reaching. We assessed the acuity of dynamic position sense in two directions, orthogonal to hand movement, which only requires spatial information, and in lin...
Source: Journal of Neurophysiology - August 1, 2017 Category: Neurology Authors: Weeks, H. M., Therrien, A. S., Bastian, A. J. Tags: Research Articles Source Type: research
A distributed neural network model for the distinct roles of medial and lateral HVC in zebra finch song production
In this report we describe a neural network organization that can explain these data, and in so doing suggests key roles for other brain nuclei in the production of song. We also suggest that syllables and the gaps between them are each coded separately by neural chains within HVC, and that the timing mechanisms for syllables and gaps are distinct. The design principles underlying this model assign distinct roles for medial and lateral HVC circuitry that explain the data on medial and lateral ablations. In addition, despite the fact that the neural coding of song sequence is distributed among several brain nuclei in our mo...
Source: Journal of Neurophysiology - August 1, 2017 Category: Neurology Authors: Galvis, D., Wu, W., Hyson, R. L., Johnson, F., Bertram, R. Tags: Research Articles Source Type: research
Estimating the implicit component of visuomotor rotation learning by constraining movement preparation time
When sensory feedback is perturbed, accurate movement is restored by a combination of implicit processes and deliberate reaiming to strategically compensate for errors. Here, we directly compare two methods used previously to dissociate implicit from explicit learning on a trial-by-trial basis: 1) asking participants to report the direction that they aim their movements, and contrasting this with the directions of the target and the movement that they actually produce, and 2) manipulating movement preparation time. By instructing participants to reaim without a sensory perturbation, we show that reaiming is possible even w...
Source: Journal of Neurophysiology - August 1, 2017 Category: Neurology Authors: Leow, L.-A., Gunn, R., Marinovic, W., Carroll, T. J. Tags: Research Articles Source Type: research
No consistent effect of cerebellar transcranial direct current stimulation on visuomotor adaptation
Cerebellar transcranial direct current stimulation (ctDCS) is known to enhance adaptation to a novel visual rotation (visuomotor adaptation), and it is suggested to hold promise as a therapeutic intervention. However, it is unknown whether this effect is robust across varying task parameters. This question is crucial if ctDCS is to be used clinically, because it must have a consistent and robust effect across a relatively wide range of behaviors. The aim of this study was to examine the effect of ctDCS on visuomotor adaptation across a wide range of task parameters that were systematically varied. Therefore, 192 young heal...
Source: Journal of Neurophysiology - August 1, 2017 Category: Neurology Authors: Jalali, R., Miall, R. C., Galea, J. M. Tags: Research Articles Source Type: research
Optimal motor synergy extraction for novel actions and virtual environments
Dimensionality reduction techniques such as factor analysis can be used to identify the smallest number of components (motor synergies) that explain motion. Lambert-Shirzad and Van der Loos (J Neurophysiol 117: 290–302, 2017) compared dimensionality reduction techniques in bimanual hand movements, concluding that nonnegative matrix factorization was the optimal technique for extracting meaningful synergies. Their results provide a useful measure for examining how the motor system deals with novel motor tasks that allow the actor to engage with a virtual environment. (Source: Journal of Neurophysiology)
Source: Journal of Neurophysiology - August 1, 2017 Category: Neurology Authors: Reader, A. T. Tags: Neuro Forum Source Type: research
The sensorimotor system minimizes prediction error for object lifting when the objects weight is uncertain
A reliable mechanism to predict the heaviness of an object is important for manipulating an object under environmental uncertainty. Recently, Cashaback et al. (Cashaback JGA, McGregor HR, Pun HCH, Buckingham G, Gribble PL. J Neurophysiol 117: 260–274, 2017) showed that for object lifting the sensorimotor system uses a strategy that minimizes prediction error when the object’s weight is uncertain. Previous research demonstrates that visually guided reaching is similarly optimized. Although this suggests a unified strategy of the sensorimotor system for object manipulation, the selected strategy appears to be tas...
Source: Journal of Neurophysiology - August 1, 2017 Category: Neurology Authors: Brooks, J., Thaler, A. Tags: Neuro Forum Source Type: research
Corrigendum
(Source: Journal of Neurophysiology)
Source: Journal of Neurophysiology - July 14, 2017 Category: Neurology Tags: Corrigenda Source Type: research
